Methods, devices, and systems for service-driven mobility management

ABSTRACT

A user equipment (UE) includes a processor configured to execute computer-executable instructions to: determine whether a required network slice/service of the UE is supported by a network node; perform at least one of a plurality of mobility management procedures, when the required network slice/service of the UE is not supported by the network node; where the plurality of mobility management procedures includes: selecting another master node (MN), or intra-MN handover or inter-MN handover to another MN; selecting or reselecting a secondary node (SN), intra-SN handover to another SN, modifying an existing SN, or adding a new SN; changing the UE&#39;s anchor node to a target new radio (NR) next generation node B (gNB) or a target evolved long term evolution (eLTE) evolved node B (eNB).

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. ProvisionalApplication No. 62/514,200 filed on Jun. 2, 2017 and entitled “METHODSAND SYSTEMS FOR SERVICE-DRIVEN MOBILITY MANAGEMENT,” Attorney Docket No.US70910 (hereinafter referred to as “US70910 application”). Thedisclosure of the US70910 application is hereby incorporated fully byreference into the present disclosure.

TECHNICAL FIELD

The present disclosure generally relates to wireless communicationmethods, and more particularly, to methods, devices, and systems forservice-driven mobility management for enhanced Long-Term Evolution(eLTE) and New Radio (NR) tight interworking.

BACKGROUND

Under the next generation (e.g., 5^(th) generation new radio) networkarchitecture, the Evolved Universal Terrestrial Radio Access (E-UTRA)and New Radio tight interworking (also referred to as “LTE-NR tightinterworking”) is a key feature for NR Non-Standalone (NSA) deployments.The LTE-NR tight interworking can also be regarded as a transition fromlegacy LTE deployments to NR Standalone (SA) deployments. The 5G NRnetwork architecture includes several options, among which Option3/3A/3X, Option 4/4A, and Option 7/7A are variants of the LTE-NR tightinterworking.¹

FIGS. 1A and 1B illustrate Options 3 and 3A, respectively, where Options3 and 3A are examples of E-UTRA-NR Dual Connectivity (EN-DC). Options 3and 3A each include an LTE eNB as an anchor node coupled to an EvolvedPacket Core (EPC), and an NR next generation Node B (gNB) coupled to theLTE eNB. In FIG. 1A, the LTE eNB connects to the EPC through an S1-Cinterface for control plane transmissions and an S1-U interface for userplane transmissions. The NR gNB control plane connects to the EPCthrough the LTE eNB, where an Xx/Xn interface couples the LTE eNB andthe NR gNB. The NR gNB user plane also connects to the EPC through theLTE eNB. In FIG. 1B, the anchor LTE eNB connects to the EPC through anS1-C interface for control plane transmissions and an S1-U interface foruser plane transmissions. The NR gNB control plane connects to the EPCthrough the LTE eNB, where an Xx/Xn interface couples the LTE eNB andthe NR gNB. Different from FIG. 1A, in FIG. 1B, the NR gNB user planemay connect directly to the EPC through an S1-U interface.

FIGS. 2A and 2B illustrate Options 4 and 4A, respectively, where Options4 and 4A are examples of NR E-UTRA Dual Connectivity (NE-DC). Options 4and 4A each include an NR gNB as an anchor node coupled to a NextGeneration Core (NGC), which is also known as a 5G-Core Network (5G-CN)or a 5G Core Network (5GC). Options 4 and 4A also each include an eLTEeNB coupled to the NR gNB. It is noted that eLTE is a radio accesstechnology with one or more next-generation evolved nodeBs (ng-eNBs)connected to a 5GC, where the ng-eNBs may also be referred to as eLTEeNBs. In this disclosure, we can use eLTE, ng-eNB, and LTE connected to5GC, interchangeably. In FIG. 2A, the NR gNB connects to the NGC throughan NG-C interface for control plane transmissions and an NG-U interfacefor user plane transmissions. The eLTE eNB control plane connects to theNGC through the NR gNB, where an Xx/Xn interface couples the eLTE eNBand the NR gNB. The eLTE eNB user plane also connects to the NGC throughthe NR gNB. In FIG. 2B, the NR gNB connects to the NGC through an NG-Cinterface for control plane transmissions and an NG-U interface for userplane transmissions. The eLTE eNB control plane connects to the NGCthrough the NR gNB, where an Xx/Xn interface couples the eLTE eNB andthe NR gNB. Different from FIG. 2A, in FIG. 2B, the eLTE eNB user planemay connect directly to the NGC through an NG-U interface.

FIGS. 3A and 3B illustrate Options 7 and 7A, respectively, where Options7 and 7A are examples of Next Generation E-UTRA-NR Dual Connectivity (NGEN-DC). Options 7 and 7A each include an eLTE eNB as an anchor nodecoupled to an NGC (e.g., 5G-CN or 5GC). Options 7 and 7A also eachinclude an NR gNB coupled to the eLTE eNB. In FIG. 3A, the eLTE eNBconnects to the NGC through an NG-C interface for control planetransmissions and an NG-U interface for user plane transmissions. The NRgNB control plane connects to the NGC through the eLTE eNB, where anXx/Xn interface couples the NR gNB and the eLTE eNB. The NR gNB userplane also connects to the NGC through the eLTE eNB. In FIG. 3B, theeLTE eNB connects to the NGC through an NG-C interface for control planetransmissions and an NG-U interface for user plane transmissions. The NRgNB control plane connects to the NGC through the eLTE eNB, where anXx/Xn interface couples the NR gNB and the eLTE eNB. Different from FIG.3A, in FIG. 3B, the NR gNB user plane may connect directly to the NGCthrough an NG-U interface.

It should be noted that the term, “eLTE”, is only used in the studyphase of TR 38.801, for example. This term may not be used in normativespecifications. However, in the present application, the term “eLTE” inthe present application may include, but is not limited to, thedefinition in the study phase of TR 38.801 and any communicationstandard with equivalent functionalities. An eLTE eNB is an evolution ofeNB that supports connectivity to both an EPC and an NGC, or to an NGConly. An eLTE eNB can also be referred to a next generation evolved NodeB (ng-eNB), which is an LTE eNB connected to a 5GC. In the presentapplication, eLTE, ng-eNB, and LTE connected to 5GC may be usedinterchangeably. In addition, an LTE eNB may not support 5G featuressuch as network slice in Radio Access Network (RAN), while an eLTE eNBcan support 5G features with higher layer network slice support. Forexample, an LTE eNB may directly connect to an EPC, but not to an NGC.An eLTE eNB may directly connect to both an EPC and an NGC, or to an NGConly. An NR gNB may support 5G features such as network slice in RANwith all layers (e.g., including SDAP (Service Data AdaptationProtocol), PDCP (Packet Data Convergence Protocol), RLC (Radio LinkControl), MAC (Medium Access Control), PHY (Physical layer) layers), andetc. It is also noted that the terms, NGC, 5GC and 5G-CN may be usedinterchangeably throughout the present application.

In the current NR study phase, LTE-NR tight interworking is agreed tohave dual connectivity (DC), which may similar to Rel-12 dualconnectivity.² The LTE eNBs, eLTE eNBs, and NR gNBs can each be a masternode and/or a secondary node. Among other differences from the Rel-12DC, in the 5G NR architecture, a secondary node may have its own RadioResource Control (RRC) entity.

As presented in each of FIGS. 4A and 4B, a user equipment (UE) iscoupled to a master node and a secondary node, where the master node andthe secondary node each have their own RRC entity. The UE has a singleRRC state machine that follows the RRC state of the master node. Eachnode generates RRC Packet Data Units (PDUs) and inter-node PDUs usingASN.1.³ In an embedded approach, the RRC PDUs and inter-node PDUsgenerated by the secondary node can be embedded with the RRC PDUsgenerated by the master node, and be transported through the master nodeto the UE. The embedded approach is used for the first configuration,for the secondary node RRC reconfiguration requiring the master node RRCreconfiguration, and for the master node RRC reconfiguration requiringthe secondary node RRC reconfiguration. In a direct approach, once theUE is configured to establish a Signaling Radio Bearer (SRB) in aSecondary Cell Group (SCG), the RRC PDUs generated by the secondary nodecan be sent directly between the secondary node and the UE. The directapproach (e.g., SCG SRB) is used for the secondary node RRCreconfiguration not requiring any coordination with the master node, andfor mobility measurement report within the secondary node. In an SCGsplit SRB approach, the RRC PDUs and inter-node PDUs generated by thesecondary node are transmitted through the lower layers (e.g., RLC, MAC,and/or PHY layers) of the master node.

In addition to LTE-NR tight interworking, network slice is anotherimportant feature of the 5G NR network architecture. With network slice,an operator can create a network customized to a specific marketscenario or for a specific service, which demands specificrequirements.⁴ To support network slice, Network Slice SelectionAssistance Information (NSSAI) may be applied, which includes one ormore Single Network Slice Selection Assistance Information (S-NSSAI).Each network slice may be uniquely identified by an S-NSSAI, which alsorepresents the slice ID used for signaling between a Radio AccessNetwork (RAN) and a Core Network (CN).

In a 5G-CN, a Network Slice Selection Function (NSSF) can select anappropriate network slice ID for a UE to satisfy its servicerequirement. A Network Slice Template (NST) may include a logicalnetwork function and resource requirements necessary to provide therequired/requested service. A Network Slice Instance (NSI) is aninstance created from an NST. Thus, network slice is also known as aconcept for describing a system behavior implemented through NSIs.⁵ EachNSI is associated with a network slice type ID (NS-ID), used to identifythe type of slice.

Currently, an LTE eNB connecting to an EPC may not support networkslice. That is, an LTE eNB does not have service differentiation, andcannot read the network slice specific messages. Furthermore, an NR gNBand an eLTE eNB each have their own network slice capabilities, but theNR gNB and the eLTE eNB may not support all the services.

Although LTE-NR tight interworking and network slice are importantfeatures of the 5G NR architecture, not all Radio Access Technologies(RATs) in the LTE-NR tight interworking deployments support networkslice.

Thus, it is desirable that LTE-NR tight interworking can support thenetwork slice, especially when an NR gNB serves as the anchor node andconnected to a 5G-CN. It is also desirable that the NR gNB/cell cansupport the RAN part of slicing (e.g., RAN part of network slice, viamultiple numerologies/TTI (Transmission Time Interval) lengths, RAN partconfiguration of network slice), and the eLTE eNB/cell can support thehigher layer network slicing. In addition, when a UE is configured withLTE-NR interworking, which may include many deployment scenarios, it isimportant to make sure that the UE connects to a suitable/appropriateRAT, which can support the UE's desired network slice(s)/service(s). Forexample, the UE may be suggested to camp to an appropriate RAT that cansupport its service during cell selection/reselection. For example, whenthe UE is in RRC_CONNECTED state and needs new networkslice(s)/service(s), the UE may be suggested to connect to anappropriate RAT, which can further support the UE's new networkslice(s)/service(s) requirement(s).

SUMMARY

The present disclosure is directed to methods, devices, and systems forservice-driven mobility management.

In a first aspect of the present application, a user equipment (UE) isdisclosed, the UE comprising: a non-transitory machine-readable mediumstoring computer-executable instructions; at least one processor coupledto the non-transitory computer-readable medium, and configured toexecute the computer-executable instructions to: determine whether arequired network slice/service of the UE is supported by a network node;perform at least one of a plurality of mobility management procedures,when the required network slice/service of the UE is not supported bythe network node; wherein the plurality of mobility managementprocedures includes: selecting another master node (MN), or intra-MNhandover or inter-MN handover to another MN; selecting or reselecting asecondary node (SN), intra-SN handover to another SN, modifying anexisting SN, or adding a new SN; changing the UE's anchor node to atarget new radio (NR) next generation node B (gNB) or a target evolvedlong term evolution (eLTE) evolved node B (eNB).

In an implementation of the first aspect, the at least one processor isfurther configured to execute the computer-executable instructions to:send a System Information (SI) request to the network node; and receivenetwork slice capability in other SI broadcast or unicast by the networknode; wherein the network slice capability indicates one or more networkslices or services supported by the network node.

In another implementation of the first aspect, at least one of theminimum SI or the other SI includes at least one of a Slice ID, aNetwork Slice Indication, or a Slice Bitmap.

In another implementation of the first aspect, the at least oneprocessor is further configured to execute the computer-executableinstructions to: send a radio resource control (RRC) message to thenetwork node for network slice support information of at least oneneighboring network node; receive the network slice support informationof the at least one neighboring network node from the other SI broadcastor unicast by the network node; determine, based on the network slicesupport information, whether the required network slice/service of theUE is supported by the at least one neighboring network node.

In another implementation of the first aspect, the network node isconnected to a 5G core network.

In another implementation of the first aspect, when selecting theanother MN or selecting or reselecting the SN, the UE measures signalsfrom a list of neighboring network nodes broadcast or unicast by thenetwork node, and selects the another MN or the SN based on themeasurement.

In another implementation of the first aspect, the UE receives a radioaccess network (RAN) notification area update through a 5G core network,the RAN notification area update includes at least one of a list of NRgNB/cell IDs or a list of RAN area IDs, wherein the list of NR gNB/cellIDs corresponds to a list of NR gNB s/cells that support the requirednetwork slice/service of the UE, and the list of RAN area IDscorresponds to a list of the RAN areas that support the required networkslice/service of the UE.

In another implementation of the first aspect, a Non-Access Stratum(NAS) of the UE provides the information of the required networkslice/service to an Access Stratum (AS) of the UE; the AS monitorssignals from the network node; the AS identifies the required networkslice/service through at least one of a Slice ID, a Network SliceIndication, and a Slice Bitmap from the signals.

In another implementation of the first aspect, the UE is configured tohave a list of barred cells that do not support the required networkslice capability.

In a second aspect of the present application, a network node isdisclosed, the network node comprising: a non-transitorymachine-readable medium storing computer-executable instructions; atleast one processor coupled to the non-transitory computer-readablemedium, and configured to execute the computer-executable instructionsto: provide network slice capability of the network node to a userequipment (UE); perform at least one of a plurality of mobilitymanagement procedures, when the network slice capability of the networknode does not support a required network slice/service of the UE;wherein the plurality of mobility management procedures includes:selecting another master node (MN), or intra-MN handover or inter-MNhandover to another MN; selecting or reselecting a secondary node (SN),intra-SN handover to another SN, or modifying an existing SN; adding anew SN; changing the UE's anchor node to a target new radio (NR) nextgeneration node B (gNB) or a target evolved long term evolution (eLTE)evolved node B (eNB).

In an implementation of the second aspect, the network node of claim 10,wherein the network node is in a master cell group or a secondary cellgroup.

In another implementation of the second aspect, the network node isconnected to a 5G core network.

In another implementation of the second aspect, the network slicecapability is broadcast or unicast by the network node via minimum SI orother SI.

In another implementation of the second aspect, at least one of theminimum SI or the other SI includes at least one of a Slice ID, aNetwork Slice Indication, or a Slice Bitmap.

In another implementation of the second aspect, the network slicecapability is broadcast or unicast through a Signaling Radio Bearer(SRB).

In another implementation of the second aspect, the at least oneprocessor is further configured to execute the computer-executableinstructions to: receive an SI request from the UE; and broadcast orunicast the network slice capability in other SI to the UE.

In another implementation of the second aspect, the at least oneprocessor is further configured to execute the computer-executableinstructions to broadcast or unicast network slice support informationof at least one neighboring network node to the UE.

In another implementation of the second aspect, the at least oneneighboring network node is connected to a 5G core network.

In another implementation of the second aspect, the network nodeprovides the UE a radio access network (RAN) notification area updatethrough the 5G core network, the RAN notification area update includesat least one of a list of NR gNB/cell IDs or a list of RAN area IDs,wherein the list of NR gNB/cell IDs corresponds to a list of NRgNBs/cells that support the required network slice/service of the UE,and the list of RAN area IDs corresponds to a list of the RAN areas thatsupport the required network slice/service of the UE.

In another implementation of the second aspect, the network nodeprovides a list of barred cells that do not support the required networkslice capability to the UE.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are diagrams illustrating 5G architectures.

FIGS. 2A and 2B are diagrams illustrating 5G architectures.

FIGS. 3A and 3B are diagrams illustrating 5G architectures.

FIGS. 4A and 4B are diagrams illustrating control plane architecturesfor LTE/eLTE and NR tight interworking.

FIG. 5A is a diagram illustrating LTE and NR tight interworking with anLTE anchor node connected to an EPC, according to an exemplaryimplementation of the present disclosure.

FIG. 5B is a diagram illustrating eLTE and NR tight interworking with aneLTE anchor node connected to a 5G-CN, according to an exemplaryimplementation of the present disclosure.

FIG. 5C is a diagram illustrating eLTE and NR tight interworking with anNR anchor node connected to a 5G-CN, according to an exemplaryimplementation of the present disclosure.

FIG. 5D is a diagram illustrating eLTE and NR tight interworking with aneLTE anchor node connected to an EPC, according to an exemplaryimplementation of the present disclosure.

FIG. 6 is a diagram illustrating an MCG SRB and an MCG split SRB with aneLTE eNB/cell as a master node, according to an exemplary implementationof the present disclosure.

FIG. 7 is a diagram illustrating an SCG SRB and an SCG split SRB with aneLTE eNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure.

FIG. 8 is a diagram illustrating an eLTE eNB/cell rejecting networkslice without providing further information, according to an exemplaryimplementation of the present disclosure.

FIG. 9 is a diagram illustrating an eLTE eNB/cell rejecting networkslice and providing further information, according to an exemplaryimplementation of the present disclosure.

FIG. 10 is a diagram illustrating an MCG bearer and an MCG split bearerwith an eLTE eNB/cell as a master node, according to an exemplaryimplementation of the present disclosure.

FIG. 11 is a diagram illustrating an SCG bearer and an SCG split bearerwith an eLTE eNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure.

FIG. 12A is a diagram illustrating an eLTE eNB/cell, as a master node,accepting network slice inquiry, according to an exemplaryimplementation of the present disclosure.

FIG. 12B is a diagram illustrating an eLTE eNB/cell, as a secondarynode, accepting network slice inquiry, according to an exemplaryimplementation of the present disclosure.

FIG. 13 is a diagram illustrating an MCG SRB and an MCG split SRB withan NR gNB/cell as a master node, according to an exemplaryimplementation of the present disclosure.

FIG. 14 is a diagram illustrating an SCG SRB and an SCG split SRB withan NR gNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure.

FIG. 15 is a diagram illustrating an NR gNB/cell rejecting network slicewithout providing further information, according to an exemplaryimplementation of the present disclosure.

FIG. 16 is a diagram illustrating an NR gNB/cell rejecting network sliceand providing further information, according to an exemplaryimplementation of the present disclosure.

FIG. 17 is a diagram illustrating an NR gNB/cell accepting network sliceinquiry, according to an exemplary implementation of the presentdisclosure.

FIG. 18 is a diagram illustrating an MCG bearer and an MCG split bearerwith an NR gNB/cell as a master node, according to an exemplaryimplementation of the present disclosure.

FIG. 19 is a diagram illustrating SCG bearer and SCG split bearer withan NR gNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure.

FIG. 20 is a diagram illustrating providing network slice via minimumSI, according to an exemplary implementation of the present disclosure.

FIG. 21 is a diagram illustrating providing network slice via other SI,according to an exemplary implementation of the present disclosure.

FIG. 22 is a diagram illustrating a neighboring cell's network slice viaother SI, according to an exemplary implementation of the presentdisclosure.

FIG. 23 is a diagram illustrating an eLTE eNB/cell broadcasting itsnetwork slice capability, according to an exemplary implementation ofthe present disclosure.

FIG. 24 is a diagram illustrating cell (re)selection based on networkslice, according to an exemplary implementation of the presentdisclosure.

FIG. 25 is a diagram illustrating inter-system intra-RAT handover,according to an exemplary implementation of the present disclosure.

FIG. 26 is a diagram illustrating RAN notification area update withnetwork slice support, according to an exemplary implementation of thepresent disclosure.

FIG. 27 is a block diagram of a node for wireless communication, inaccordance with various aspects of the present disclosure.

DETAILED DESCRIPTION

The following description contains specific information pertaining toexemplary implementations in the present disclosure. The drawings in thepresent disclosure and their accompanying detailed description aredirected to merely exemplary implementations. However, the presentdisclosure is not limited to merely these exemplary implementations.Other variations and implementations of the present disclosure willoccur to those skilled in the art. Unless noted otherwise, like orcorresponding elements among the figures may be indicated by like orcorresponding reference numerals. Moreover, the drawings andillustrations in the present disclosure are generally not to scale, andare not intended to correspond to actual relative dimensions.

In some implementations, this disclosure may include the language, forexample, “at least one of [element A] or [element B]”. This language mayrefer to one or more of the elements. For example, “at least one of A orB” may refer to “A”, “B”, or “A and B”. In other words, “at least one ofA or B” may refer to “at least one of A and at least one of B,” or “atleast of either A or B.” In some implementations, this disclosure mayinclude the language, for example, “[element A], [element B], and/or[element C].” This language may refer to either of the elements or anycombination thereof. In other words, “A, B, and/or C” may refer to “A”,“B”, “C”, “A and B”, “A and C”, “B and C”, or “A, B, and C”.

In some of the exemplary implementations, an EPC may not support networkslice, unlike the NGC (e.g., 5G-CN and 5GC) which may support networkslice. In some of the exemplary implementations, an LTE eNB may notsupport network slice, unlike the eLTE eNB and NR gNB which may supportnetwork slice. In some of the exemplary implementations, an eLTEeNB/cell may not support RAN part of slicing (e.g., RAN part of networkslice, via multiple numerologies/TTI lengths, RAN part configuration ofnetwork slice), but may support network slice from RRC, SDAP, and PDCPlayers. In some of the exemplary implementations, an NR gNB/cell maysupport RAN part of slicing from an RRC layer and an SDAP layer to a PHYlayer (e.g., via different numerologies/TTI lengths). When a CN is a5G-CN, the CN may support the storage and selection of network slice.For example, a 5G-CN may store the network slice/service information(e.g., NS-IDs, S-NSSAIs, and/or slice IDs) of each registered NRgNB/cell and eLTE eNB/cell. The 5G-CN may also select the proper NRgNB/cell and eLTE eNB/cell for the UE's network slice/service request.It is noted that the capabilities of network slice/service supported byeach RAT/cell may be different. In some of the exemplaryimplementations, an eLTE eNB and/or NR gNB may not have the capabilityto support all network slices/services defined by the core network. Insome of the exemplary implementations, the capabilities of these networkentities are summarized in Table 1. It is noted that the networkslices/services supported by RATs may be a subset of the networkslices/services supported by the CN.

TABLE 1 Network Slice Capability of Different Network Entities RadioAccess Technology Core Network NR gNB eLTE eNB LTE eNB 5G-CN EPC NetworkSlice Supported Supported Supported

In some of the exemplary implementations, NR gNBs and eLTE eNBs maygenerate/read/transmit/receive/forward network slice/service related RRCmessages. The NR gNBs and eLTE eNBs may support SDAP and PDCP to connectto a 5GC. The NR gNBs may further provide RAN part of slicing (e.g., RANpart of network slice, via multiple numerologies/TTI lengths, RAN partconfiguration of network slice) to support different networkslices/services. Based on the 5G NR architecture and the capability ofnetwork slice of each network entity, four cases are of interest areshown in FIGS. 5A, 5B, 5C, and 5D, where control plan connections areshown. In FIG. 5A, Case 500A refers to LTE and NR tight interworking andLTE as the anchor connecting to EPC. In FIG. 5B, Case 500B refers toeLTE and NR tight interworking and eLTE as the anchor connecting to the5G-CN (e.g., Next Generation E-UTRAN NR Dual Connectivity, NGEN-DC). InFIG. 5C, Case 500C refers to eLTE and NR tight interworking (e.g., NRE-UTRAN Dual Connectivity, NE-DC) and NR as the anchor connecting to the5G-CN. In FIG. 5D, Case 500D refers to eLTE and NR tight interworkingand eLTE as the anchor connecting to the EPC.

In the implementations illustrated in Case 500B of FIG. 5B, Case 500C ofFIG. 5C, and Case 500D of FIG. 5D, the master node and secondary nodemay be either an eLTE eNB/cell or an NR gNB/cell, and the core networkmay be either an EPC or a 5G-CN. In other words, the eLTE eNB/cell canbe either a master node or a secondary node. When the eLTE eNB/cell isthe master node, the secondary node is NR gNB/cell, and the core networkis EPC in Case 500D or 5GC in Case 500B. When the eLTE eNB/cell is thesecondary node, the master node is an NR gNB/cell, and the core networkis 5GC in Case 500C. The objective is to ensure that the UE configuredwith eLTE-NR tight interworking, such as in Cases 500B, 500C, and 500D,can connect to the appropriate RAT, which supports the UE'srequired/requested or updated network slices and/or services.

There are several cases where a UE may need assistance to connect to asuitable node that supports the UE's specific network slice(s) and/orservice(s). For example, when a UE performs initial access, the UE mayconnect to a master node, which cannot support its network slice and/orservice requirements. In another case, even after the UE performsinitial access and connects to a suitable master node, which supportsits initial network slice, the master node may become unsuitable whenthe UE changes/updates the network slice, for example, in RRC_CONNECTEDstate. In another case, a UE with network slice capability turns to thesecondary node for the network slice/service. Exemplary implementationsof the present application describe various methods/mechanisms forensuring a UE connect to a suitable node, which supports the UE'sspecific network slice(s) and/or service(s).

It is noted that the cell IDs and base station IDs in the presentapplication may refer to NR gNB ID, NR cell ID, (e)LTE eNB ID, (e)LTEcell ID, global unique base station ID (e.g., PLMN ID plus eNB ID forLTE), unique base station ID in a PLMN (e.g., eNB ID for LTE),NR/E-UTRAN Cell Identity (e.g., eNB ID plus cell ID for LTE), globalNR/E-UTRAN Cell Identity (e.g., PLMN ID plus eNB ID plus cell ID forLTE, Tracking Area Code plus PLMN ID plus cell ID for NR), PCI (PhysicalCell Identifier) which is derived from PSS (Primary SynchronizationSignals) and/or SSS (Secondary Synchronization Signals).

Case 1: UE Reveals its Network Slice Capability to eLTE eNB/Cell.

A UE may reveal its network slice capability and/or requirement to aneLTE eNB/cell through an RRC message. The eLTE eNB/cell may be a masternode/cell in a Master Cell Group (MCG) as shown in FIGS. 5B and 5D, or asecondary node/cell a Secondary Cell Group (SCG) as shown in FIG. 5C.

FIG. 6 is a diagram illustrating an MCG SRB and an MCG split SRB with aneLTE eNB/cell as a master node, according to an exemplary implementationof the present disclosure. As shown in FIG. 6, when eLTE eNB/cell 620 isa master node, the control signaling revealing a UE's network slicecapability, between the UE and eLTE eNB/cell 620, may be providedthrough one or more MCG Signaling Radio Bearers (SRBs) and/or one ormore MCG split SRBs. As shown in FIG. 6, eLTE eNB/cell 620 may be amaster node in an MCG, and may include RRC layer 622, PDCP layer 624,RLC layer 626, MAC layer 628, and PHY layer 630. NR gNB/cell 640 may bea secondary node in an SCG, and may include RRC layer 642, PDCP layer644, RLC layer 646, MAC layer 648, and PHY layer 650. The controlsignaling revealing the UE's network slice capability, between the UEand eLTE eNB/cell 620, may be provided through an MCG SRB via RRC layer622, PDCP layer 624, RLC layer 626, MAC layer 628, and PHY layer 630 ofeLTE eNB/cell 620. Instead of, or in addition to, the control signalingbeing provided through the MCG SRB, the control signaling revealing theUE's network slice capability, between the UE and eLTE eNB/cell 620, maybe provided through an MCG split SRB, via RRC layer 622 and PDCP layer624 of eLTE eNB/cell 620, and via RLC layer 646, MAC layer 648, and PHYlayer 650 of NR gNB/cell 640 (e.g., secondary node in an SCG).

FIG. 7 is a diagram illustrating an SCG SRB and an SCG split SRB with aneLTE eNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure. It is noted that SCG SRB mayalso be regarded as SRB3. As shown in FIG. 7, when eLTE eNB/cell 720 isa secondary node, the control signaling revealing the UE's network slicecapability, between the UE and eLTE eNB/cell 720, may be through one ormore SCG SRBs and/or one or more SCG split SRBs. As shown in FIG. 7, NRgNB/cell 740 may be a master node in an MCG, and may include RRC layer742, PDCP layer 744, RLC layer 746, MAC layer 748, and PHY layer 750.eLTE eNB/cell 720 is a secondary node in an SCG, and may include RRClayer 722, PDCP layer 724, RLC layer 726, MAC layer 728, and PHY layer730. The control signaling revealing the UE's network slice capability,between the UE and eLTE eNB/cell 720, can be through an SCG SRB throughRRC layer 722, PDCP layer 724, RLC layer 726, MAC layer 728, and PHYlayer 730 of eLTE eNB/cell 720. Instead of, or in addition to, thecontrol signaling being provided through the SCG SRB, the controlsignaling revealing the UE's network slice capability, between the UEand eLTE eNB/cell 720, may be through an SCG split SRB, via RRC layer722 and PDCP layer 724 of eLTE eNB/cell 720, and via RLC layer 746, MAClayer 748, and PHY layer 750 of NR gNB/cell 740 (e.g., the master nodein an MCG).

As illustrated in FIGS. 8, 9, 12A and 12B, a UE reveals its networkslice capability and/or service requirement for network slice in an RRCmessage (e.g., RRC Connection Request or RRC or RRC Connection SetupComplete or Connection Establishment or RRC System Information Request).The RRC message may include a UE ID to reveal the UE identity. The RRCmessage may include slice IDs and/or network slice type ID (NS-ID) todirectly identify the type of network slice and/or required/requestedservice the UE needs. In another exemplary implementation, a slicebitmap may be used to directly identify the type of network slice and/orrequired/requested service in the RRC message. For example, the slicebitmap may include preconfigured N bits (e.g., N supported networkslices/services), with a bit “1” meaning the corresponding networkslice/service is supported, and a bit “0” meaning the correspondingnetwork slice/service is not supported.

It should be noted that, in the present application, slice IDs in allfigures are used for illustration purpose only. That is, the slice IDscan be replaced with slice bitmaps to identify the indicated networkslices/services. The cause value in an RRC message may be ‘networkslice’ corresponding to a NAS (Non-Access Stratum) procedure. Moreover,the RRC message may carry the network slice indication (NS Indication),to indicate the network slice requirement instead of explicitlyrevealing the slice service type.

In exemplary implementations of the present application, the eLTEeNB/cell, after receiving the RRC message, may take the followingactions: Case 1A—reject through an RRC message without providing anyfurther information; Case 1B—reject through an RRC message and provideassisting information in the RRC message; Case 1C—accept through an RRCmessage. It should be noted that the RRC message exchange between the UEand the eLTE eNB is not limited to the eLTE eNB as a master node or asecondary node under dual-connectivity operation. For example, the RRCmessage exchange between the UE and the eLTE eNB may also be applicablewhen the eLTE eNB is a standalone node.

Case 1A: eLTE eNB/Cell Rejects UE's Request without Providing FurtherInformation.

FIG. 8 is a diagram illustrating an eLTE eNB/cell rejecting networkslice without providing further information, according to an exemplaryimplementation of the present disclosure. As illustrated in FIG. 8, inaction 812, UE 802 sends a network slice/service request through an RRCmessage, such as an RRC Message for Request (e.g., including UE ID,Slice IDs, NS Indication, and/or Slice Bitmap) to eLTE eNB/cell 804. Inaction 814, eLTE eNB/cell 804 responds with an RRC Message for Rejection(e.g., Cause: no network slice support). That is, eLTE eNB/cell 804reads the RRC message from UE 802, and directly responds with an RRCdedicated signaling to reject the network slice support without anyfurther information. In one example, eLTE eNB/cell 804 responds with theRRC dedicated signaling to reject the network slice support because thecore network such as an EPC cannot recognize/support the establishmentcause of network slice (e.g., Case 500D in FIG. 5D). In another example,eLTE eNB/cell 804 responds with the RRC dedicated signaling to rejectthe network slice support because the EPC does not support network slicefunction even though eLTE eNB/cell 804 recognizes the slice IDs and/orNS Indication and/or slice bitmap. In yet another example, eLTE eNB/cell804 responds with the RRC dedicated signaling to reject the networkslice support because eLTE eNB/cell 804 itself cannot support therequired/requested network slice/service, and/or eLTE eNB/cell 804 isconfigured not to perform the network slice inquiry to other nodes/cells(e.g., eLTE eNB s/cells and NR gNBs/cells in MCG and SCG), and/or eLTEeNB/cell 804 attempts to find a suitable eLTE eNB/cell and NR gNB/cellbut ends up unsuccessful. It may be also because that UE 802 is notconfigured with eLTE-NR interworking so that eLTE eNB/cell 804 cannotforward the RRC message to other nodes/cells in MCG or SCG (e.g., eLTEeNB s/cells and NR gNB s/cells) for network slice inquiry. In general,failure cases occur so that eLTE eNB/cell 804 rejects UE 802's request.Once eLTE eNB/cell 804 rejects the network slice support via RRCsignaling, the RRC message for rejection (e.g., RRC Message forRejection) can involve a cause (e.g., no network slice support as shownin FIG. 8) or any of the above mentioned reasons.

In one exemplary implementation, the RRC message for rejection mayinclude a prohibit timer. The prohibit timer may be activated eitherwhen eLTE eNB/cell 804 sends the RRC message for rejection or when UE802 receives the RRC message for rejection. Once the prohibit timer isactivated, UE 802 is not allowed to camp to eLTE eNB/cell 804 until theprohibit timer expires. In another exemplary implementation, once theprohibit timer is activated, UE 802 cannot request the same networkslice/service from any base station until the prohibit timer expires.The prohibit timer stops either when the prohibit timer expires or wheneLTE eNB/cell 804 updates its network slice support (e.g., UE 802 mayconstantly monitor slice support while the prohibit timer is running)Upon receiving the RRC dedicated signaling from eLTE eNB/cell 804 fornetwork slice support rejection, UE 802 may perform the MCG-relatedprocedures (e.g., handover to another master node that supports therequired/requested network slice/service, or the inter-MN (master node)handover without the change of the secondary node), or SCG-relatedprocedures (e.g., secondary node change/addition/modification, or beamchange/addition/modification, so that the new/target master node orsecondary node or beam supports the required/requested networkslice/service). In the present application, UE 802 may havemulti-connectivity with a number of base stations to support the networkslice/service. In the present application, it is noted that UE 802 mayrecord the cell ID that can't support respective network slicing andhave corresponding prioritization (e.g. low priority) for cell(re-)selection, handover and the selection of master nodes and secondarynodes.

Case 1B: eLTE eNB/Cell Rejects UE's Request and Provides FurtherInformation.

FIG. 9 is a diagram illustrating an eLTE eNB/cell rejecting networkslice and providing further information, according to an exemplaryimplementation of the present disclosure. As illustrated in FIG. 9, inaction 912, UE 902 sends a network slice/service request through an RRCmessage, such as an RRC Message for Request (e.g., including UE ID,Slice IDs/NS Indication/Slice Bitmap) to eLTE eNB/cell 904. In action914, although eLTE eNB/cell 904 rejects the required/requested networkslice/service (the cause may be the same in Case 1A), eLTE eNB/cell 904may provide UE 902 with information of other eLTE eNBs/cells and NRgNBs/cells in the RRC message to assist UE 902 to connect to a suitableNR gNB/cell or eLTE gNB/cell that can provide UE 902's requested networkslice/service. For example, eLTE eNB/cell 904 is configured to sendnetwork slice inquiries to other nodes/cells or the core network.

According to implementations of the present application, there are twoapproaches to acquire the information of network slice/service support.The first approach is direct coordination with other eLTE eNB s/cellsand NR gNB s/cells. The second approach is to send the inquiry to thecore network, such as a 5G-CN.

In the first approach, eLTE eNB/cell 904 sends an Xx/Xn messageincluding UE 902's requested network slice/service information (e.g.,Slice IDs/NS Indication/Slice Bitmap) to other eLTE eNB s/cells and NRgNB s/cells. Those eLTE eNB s/cells and NR gNB s/cells, which cansupport UE 902's requested network slice/service, respond to eLTEeNB/cell 904 with acknowledgement so that eLTE eNB/cell 904 can provideUE 902 with a list of IDs of eLTE eNB s/cells and NR gNB s/cells/beamswhich can satisfy UE 902's network slice/service request.

In the second approach, the core network (e.g., 5G-CN) may already havestored what types of network slice/service are supported by which eLTEeNBs/cells and NR gNBs/cells. Therefore, eLTE eNB/cell 904 may send NG-Csignaling to the core network including UE 902's requested networkslice/service. The core network may retrieve the information of suitableeLTE eNBs/cells and NR gNBs/cells, and provide a list of suitable eLTEeNB/cell and NR gNB/cell IDs to eLTE eNB/cell 904 through NG-Csignaling. eLTE eNB/cell 904 may either first filter the list (e.g.,remove the blocked cells) before transmitting it to UE 902, or directlytransmit the list to UE 902 without any modification.

After eLTE eNB/cell 904 acquires the information regarding which eLTEeNB s/cells and NR gNBs/cells support UE 902's network slice/servicerequest, eLTE eNB/cell 904 may respond to UE 902 with an RRC message(e.g., RRC Connection Reject or RRC Connection Reconfiguration), wherethe RRC message includes information such as target NR gNB/cell/beam orLTE eNB/cell or eLTE eNB/cell ID, and/or a list of suitable NRgNB/cell/beam IDs and/or LTE eNB/cell IDs and/or eLTE eNB/cell IDs,and/or specific preamble of the target NR gNB/cell or LTE eNB/cell oreLTE eNB/cell, and/or target NR SS (Synchronization Signal)block/burst/burst set configuration, and/or a list of suitable NR SSblock/burst/burst set configurations, as illustrated in FIG. 9. The SSblock/burst/burst set may include synchronization signals and/orreference signals for UE 902 to do measurements. Thus, UE 902 mayperform measurements to the target NR gNB/cell/beam or LTE eNB/cell oreLTE eNB/cell or a list of NR gNBs/cells/beams or LTE eNBs/cells or eLTEeNBs/cells. Moreover, with the information of preamble, the targetnode/cell may regard UE 902 as a special UE, and provide UE 902 withprivilege during the random access procedure. Providing the beaminformation and the SS block/burst/burst set configurations to UE 902may be beneficial, when different beams can support different networkslices/services (different numerology/TTI length configurations) in NR.

In other implementations, eLTE eNB/cell 904 may directly select a targetNR gNB/cell/beam or a target LTE eNB/cell or a target eLTE eNB/cell forUE 902, and send an RRC message (e.g., RRC Connection Reject or RRCConnection Reconfiguration) including the cell ID, and/or preamble,and/or beam ID (if supported), and/or SS block/burst/burst setconfiguration (if supported) of target NR gNB/cell or a target LTEeNB/cell or a target eLTE eNB/cell to UE 902. UE 902 may perform thehandover to another master node which supports the required/requestednetwork slice/service, or the inter-MN handover without the change ofthe secondary node, or secondary node change/addition/modification sothat the new/target secondary node supports the required/requestednetwork slice/service. In the present implementation, UE 902 may havemulti-connectivity with a number of base stations to support the networkslice/service. It is noted that the NR gNBs/cells and eLTE eNBs/cellschosen by eLTE eNB/cell 904 may at least provide the network slicefunction, and optionally provide UE 902's specific requested networkslice/service.

In other implementations, the RRC message for rejection may include aprohibit timer. The prohibit timer may be activated either when eLTEeNB/cell 904 sends the RRC message for rejection or when UE 902 receivesthis RRC message for rejection. Once the prohibit timer is activated, UE902 may not be allowed to camp to eLTE eNB/cell 904 until the prohibittimer expires. In another implementation, once the prohibit timer isactivated, UE 902 cannot request the same network slice/service from anybase station until the prohibit timer expires. The prohibit timer stopseither when the timer expires or when eLTE eNB/cell 904 updates itsnetwork slice support (e.g., UE 902 may constantly monitor slice supportwhile the prohibit timer is running).

Case 1C: eLTE eNB/Cell Accepts UE's Request with RRC Message.

An eLTE eNB/cell reads the RRC message including a UE's networkslice/service request, and decides to provide such network slice/serviceon its own.

FIG. 10 is a diagram illustrating an MCG bearer and an MCG split bearer(e.g., a split bearer) with an eLTE eNB/cell as a master node, accordingto an exemplary implementation of the present disclosure. When eLTEeNB/cell 1020 is a master node, the network slice may be providedthrough an MCG split bearer and/or an MCG bearer, as shown in FIG. 10.For example, eLTE eNB/cell 1020 may reply to the UE with an RRC message(e.g., RRC Connection Setup or RRC Reconfiguration) through an MCG SRBor an MCG split SRB, indicating the related parameters to build the MCGsplit bearer.

As shown in FIG. 10, eLTE eNB/cell 1020 may be a master node in an MCG,and may include SDAP layer 1022, PDCP layer 1024, RLC layer 1026, MAClayer 1028, and PHY layer 1030. NR gNB/cell 1040 may be a secondary nodein the SCG, and may include SDAP layer 1042, PDCP layer 1044, RLC layer1046, MAC layer 1048, and PHY layer 1050. The network slice may beprovided through an MCG bearer via SDAP layer 1022, PDCP layer 1024, RLClayer 1026, MAC layer 1028, and PHY layer 1030 of eLTE eNB/cell 1020.Instead of, or in addition to, the network slice being provided throughthe MCG bearer, the network slice may be provided through an MCG splitbearer via SDAP layer 1022, PDCP layer 1024 of eLTE eNB/cell 1020, andvia RLC layer 1046, MAC layer 1048, and PHY layer 1050 of NR gNB/cell1040 (e.g., a secondary node). In some implementations, NR gNB/cell 1040is a selected NR gNB/cell that supports the RAN part of slicing. In someimplementations, the selected NR gNB/cell may utilize an existingsecondary cell in an SCG or add a new secondary cell to the SCG. Thus,SCG-related procedures may be utilized to realize the MCG split bearer.

FIG. 11 is a diagram illustrating an SCG bearer and an SCG split bearer(e.g., a split bearer) with an eLTE eNB/cell as a secondary node,according to an exemplary implementation of the present disclosure. WheneLTE eNB/cell 1120 is a secondary node, the network slice may beprovided through an SCG split bearer and/or an SCG bearer, as shown inFIG. 11. For example, eLTE eNB/cell 1120 may reply to the UE with an RRCmessage (e.g., RRC Connection Setup or RRC Reconfiguration) through anSCG SRB and/or an SCG split SRB, indicating the related parameters tobuild the SCG split bearer.

As shown in FIG. 11, eLTE eNB/cell 1120 may be a secondary node in anSCG, and may include SDAP layer 1122, PDCP layer 1124, RLC layer 1126,MAC layer 1128, and PHY layer 1130. NR gNB/cell 1040 may be a secondarynode in the MCG, and may include SDAP layer 1142, PDCP layer 1144, RLClayer 1146, MAC layer 1148, and PHY layer 1150. The network slice may beprovided through an SCG bearer via SDAP layer 1122, PDCP layer 1124, RLClayer 1126, MAC layer 1128, and PHY layer 1130 of eLTE eNB/cell 1120.Instead of, or in addition to, the network slice being provided throughthe SCG bearer, the network slice may be provided through an SCG splitbearer via SDAP layer 1122, PDCP layer 1124 of eLTE eNB/cell 1120, andvia RLC layer 1146, MAC layer 1148, and PHY layer 1150 of NR gNB/cell1140 (e.g., a master node). In some implementations, NR gNB/cell 1140 isa selected NR gNB/cell that supports the RAN part of slicing. In someimplementations, the selected NR gNB/cell may utilize an existing mastercell in an MCG or add a new master cell to the MCG. Thus, MCG-relatedprocedures may be utilized to realize the SCG split bearer.

It is noted that SCG-related procedures 1214A in FIG. 12A, andMCG-related procedures 1214B in FIG. 12B, may include beam-leveloperations, such as beam addition (e.g., add NR beams that support therequired/requested network slice), beam change (e.g., change from theserving NR beam to a new beam that support the required/requestednetwork slice), and beam modification (e.g., modify a beam so that thebeam supports the required/requested network slice).

After SCG-related procedures 1214A in FIG. 12A, and MCG-relatedprocedures 1214B in FIG. 12B, eLTE eNB/cell 1204 informs UE 1202 usingan RRC message (e.g., RRC Connection Setup, RRC Configuration, or RRCReconfiguration). After SCG-related procedures 1214A in FIG. 12A, andMCG-related procedures 1214B in FIG. 12B, eLTE eNB/cell 1204 hasestablished connection to NR gNB/cell 1206 for the RAN part of slicing.The control signaling exchange for the SCG-related or MCG-relatedprocedures occurs in an Xx/Xn interface. The exchanged information mayinclude UE ID, Slice IDs, Slice Bitmap, NS Indication, target NRgNB/cell/beam, LTE eNB/cell or eLTE eNB/cell ID, a list of suitable NRgNB/cell/beam IDs and/or LTE eNB/cell IDs and/or eLTE eNB/cell IDs,and/or specific preamble of the target NR gNB/cell or LTE eNB/cell oreLTE eNB/cell, and/or target NR SS block/burst/burst set configuration,and/or a list of suitable NR SS block/burst/burst set configurations.

After receiving the RRC message (e.g., RRC Connection Setup, RRCConfiguration, or RRC Reconfiguration) from eLTE eNB/cell 1204, UE 1202sends an RRC message in action 1218, (e.g., an RRC Connection Complete,an RRC Configuration Complete, or an RRC Connection ReconfigurationComplete) to eLTE eNB/cell 1204 through an MCG SRB or an MCG split SRBif eLTE eNB/cell 1204 is a master node in an MCG, or through an SCG SRBor an SCG split SRB if eLTE eNB/cell 1204 is a secondary node in an SCG.

Case 2: UE Reveals its Network Slice Capability to NR gNB/Cell.

A UE may reveal its network slice capability and/or requirement to an NRgNB/cell through an RRC message. The NR gNB/cell may be a master node ina Master Cell Group (MCG) as shown in FIG. 5C, or a secondary node in aSecondary Cell Group (SCG) as shown in FIGS. 5B and 5D.

FIG. 13 is a diagram illustrating an MCG SRB and an MCG split SRB withan NR gNB/cell as a master node, according to an exemplaryimplementation of the present disclosure. As shown in FIG. 13, when NRgNB/cell 1340 is a master node, the control signaling revealing a UE'snetwork slice capability (e.g., an RRC message), between the UE and NRgNB/cell 1340, may be provided through one or more MCG SRBs and/or oneor more MCG split SRBs. As shown in FIG. 13, NR gNB/cell 1340 may be amaster node in an MCG, and may include RRC layer 1342, PDCP layer 1344,RLC layer 1346, MAC layer 1348, and PHY layer 1350. eLTE eNB/cell 1320may be a secondary node in an SCG, and may include RRC layer 1322, PDCPlayer 1324, RLC layer 1326, MAC layer 1328, and PHY layer 1330. Thecontrol signaling revealing the UE's network slice capability, betweenUE and NR gNB/cell 1340, may be provided through an MCG SRB via RRClayer 1342, PDCP layer 1344, RLC layer 1346, MAC layer 1348, and PHYlayer 1350 of NR gNB/cell 1340. Instead of, or in addition to, thecontrol signaling being provided through the MCG SRB, the controlsignaling revealing the UE's network slice capability, between the UEand NR gNB/cell 1340, may be provided through an MCG split SRB, via RRClayer 1342 and PDCP layer 1344 of NR gNB/cell 1340, and via RLC layer1326, MAC layer 1328, and PHY layer 1330 of eLTE eNB/cell 1320 (e.g., asecondary node in an SCG).

FIG. 14 is a diagram illustrating an SCG SRB and an SCG split SRB withan NR gNB/cell as a secondary node, according to an exemplaryimplementation of the present disclosure. It is noted that SCG SRB mayalso be regarded as SRB3. As shown in FIG. 14, when NR gNB/cell 1440 isa secondary node, the control signaling revealing a UE's network slicecapability, between the UE and NR gNB/cell 1440, may be provided throughone or more SCG SRBs and/or one or more SCG split SRBs. As shown in FIG.14, eLTE eNB/cell 1420 may be a master node in an MCG, and may includeRRC layer 1422, PDCP layer 1424, RLC layer 1426, MAC layer 1428, and PHYlayer 1430. NR gNB/cell 1440 may be a secondary node in an SCG, and mayinclude RRC layer 1442, PDCP layer 1444, RLC layer 1446, MAC layer 1448,and PHY layer 1450. The control signaling revealing the UE's networkslice capability, between the UE and NR gNB/cell 1440, may be providedthrough an SCG SRB via RRC layer 1442, PDCP layer 1444, RLC layer 1446,MAC layer 1448, and PHY layer 1450 of NR gNB/cell 1440.

Instead of, or in addition to, the control signaling being providedthrough the SCG SRB, the control signaling revealing the UE's networkslice capability, between the UE and NR gNB/cell 1440, may be providedthrough an SCG split SRB, via RRC layer 1442 and PDCP layer 1444 of NRgNB/cell 1440, and via RLC layer 1426, MAC layer 1428, and PHY layer1430 of eLTE eNB/cell 1420 (e.g., a master node in an MCG). In someimplementations, the control signaling (e.g., RRC messages) between thesecondary node NR gNB/cell 1440 (e.g., a secondary node in an SCG) andthe UE may be transmitted via the embedded approach described herein.

In accordance with implementations as illustrated in FIGS. 15, 16, and17 of the present disclosure, a UE may reveal its network slicecapability and/or service requirement in an RRC message (e.g., an RRCConnection Request or RRC Connection Setup Complete or an RRC ConnectionEstablishment). The RRC message may include a UE ID to reveal the UEidentity. The RRC message may include slice IDs and/or network slicetype ID (NS-ID) to directly identify the type of network slice and/orrequired/requested service. In another exemplary implementation, a slicebitmap may be used to directly identify the type of network slice and/orrequired/requested service in the RRC message. For example, the slicebitmap may include preconfigured N bits (e.g., N supported networkslices/services), with a bit “1” meaning the corresponding networkslice/service is supported, and a bit “0” meaning the correspondingnetwork slice/service is not supported.

It should be noted that, in the present application, slice IDs in thefigures are merely used for illustration purposes. That is, the sliceIDs may be replaced with slice bitmaps to identify the indicated networkslice(s)/service(s). The cause value in an RRC message may be “networkslice” corresponding to a NAS procedure. Moreover, the RRC message maycarry the network slice indication (NS Indication), to indicate thenetwork slice requirement instead of explicitly revealing the sliceservice type.

The RRC entity of the NR gNB/cell may recognize whether therequired/requested service or the required/requested network slicefunction is supported. It is noted that the RRC entity of the NRgNB/cell is preconfigured for RAN part of slicing (e.g., multiplenumerologies/TTI lengths for different slices) so that the NR gNB/cellcan identify whether it supports the UE's service request or not.

In exemplary implementations of the present application, the NRgNB/cell, after receiving the RRC message, may take the followingactions: Case 2A—reject through an RRC message without providing anyfurther information; Case 2B—reject through an RRC message and provideassisting information in the RRC message; Case 2C—accept through an RRCmessage. It should be noted that the RRC message exchange between the UEand the NR gNB is not limited to the NR gNB as a master node or asecondary node under dual-connectivity operation. For example, the RRCmessage exchange between the UE and the NR gNB may also be applicablewhen the NR gNB is a standalone node.

Case 2A: NR gNB/Cell Rejects UE's Request without Providing FurtherInformation.

FIG. 15 is a diagram illustrating an NR gNB/cell rejecting network slicewithout providing further information, according to an exemplaryimplementation of the present disclosure. As illustrated in FIG. 15, inaction 1512, UE 1502 sends a network slice/service request through anRRC message, such as an RRC Connection Request or RRC Connection SetupComplete (e.g., including UE ID, Slice IDs, NS Indication, and/or SliceBitmap) to NR gNB/cell 1506. In action 1514, NR gNB/cell 1506 respondswith an RRC Connection Rejection (e.g., Cause: no network slicesupport). That is, NR gNB/cell 1506 reads the RRC message from UE 1502,and directly responds with an RRC dedicated signaling to reject thenetwork slice support without providing any further information. In oneexample, NR gNB/cell 1506 responds with the RRC dedicated signaling toreject the network slice support because the NR gNB/cell and/or eLTE eNBcannot support the required/requested network slice/service. In anotherexample, NR gNB/cell 1506 responds with the RRC dedicated signaling toreject the network slice support because the NR gNB/cell refuses tosupport the required/requested network slice/service (e.g., due to noavailable network resource) even though it can. In yet another example,NR gNB/cell 1506 responds with the RRC dedicated signaling to reject thenetwork slice support because some failure cases occur in the network.After NR gNB/cell 1506 rejects UE 1502's request via the RRC message,the RRC message for rejection can involve a cause (e.g., no networkslice support as shown in FIG. 15) or any of the above mentionedreasons.

In one exemplary implementation, the RRC message for rejection mayinclude a prohibit timer. The prohibit timer may be activated eitherwhen NR gNB/cell 1506 sends the RRC message for rejection or when UE1502 receives the RRC message for rejection. Once the prohibit timer isactivated, UE 1502 is not allowed to camp to NR gNB/cell 1506 until theprohibit timer expires. In another exemplary implementation, once theprohibit timer is activated, UE 1502 cannot request the same networkslice/service from any base station until the prohibit timer expires.The prohibit timer stops either when the prohibit timer expires or whenthe NR gNB/cell updates its network slice support (e.g., UE 1502 mayconstantly monitor network slice support while the prohibit timer isrunning) Upon receiving the RRC dedicated signaling from NR gNB/cell1506 for network slice support rejection, UE 1502 may perform theMCG-related procedures (e.g., handover to another master node thatsupports the required/requested network slice/service, or the inter-MN(master node) handover without the change of the secondary node), orSCG-related procedures (e.g., secondary nodechange/addition/modification, or beam change/addition/modification, sothat the new/target master node or secondary node or beam supports therequired/requested network slice/service). In the present application,UE 1502 may have multi-connectivity with a number of base stations tosupport the network slice/service. In the present application, it isnoted that UE 1502 may record the cell ID that cannot support respectivenetwork slicing and have corresponding prioritization (e.g. lowpriority) for cell (re-)selection, handover and the selection of masternodes and secondary nodes.

Case 2B: NR gNB/Cell Rejects UE's Request and Provides FurtherInformation.

FIG. 16 is a diagram illustrating an NR gNB/cell rejecting network sliceand providing further information, according to an exemplaryimplementation of the present disclosure. As illustrated in FIG. 16, inaction 1612, UE 1602 sends a network slice/service request through anRRC message, such as an RRC Message for Request (e.g., including UE ID,Slice IDs/NS Indication/Slice Bitmap) to NR gNB/cell 1606.

In action 1614, NR gNB/cell 1606 cannot establish an RRC connection forUE 1602's network slice/service requirement (the cause may be the samein Case 2A), and NR gNB/cell 1606 replies with an RRC message (e.g., RRCMessage for Rejection or RRC Connection Reject). Nevertheless, NRgNB/cell 1606 may provide further information of other NR gNBs/cells andeLTE eNB s/cells in the RRC message to assist UE 1602 to connect to asuitable NR gNB/cell or eLTE gNB/cell that can provide UE 1602'srequired/requested network slice/service. NR gNB/cell 1606 is configuredto send network slice inquiries to other nodes/cells or the corenetwork.

According to implementations of the present application, there are twoapproaches to acquire the information of network slice/service support.The first approach is direct coordination with other eLTE eNBs/cells andNR gNBs/cells. The second approach is to send the inquiry to the corenetwork, such as a 5G-CN.

In the first approach, NR gNB/cell 1606 sends the Xx/Xn messageincluding UE 1602's request network slice/service information (e.g.,Slice IDs, NS Indication, or Slice Bitmap) to other eLTE eNB s/cells andNR gNB s/cells. Those eLTE eNB s/cells and NR gNB s/cells, which supportUE 1602's request network slice/service, respond to NR gNB/cell 1606with acknowledgement so that NR gNB/cell 1606 can provide UE 1602 with alist of IDs of eLTE eNBs/cells and NR gNBs/cells/beams which can satisfyUE 1602's network slice/service request.

In the second approach, the core network (e.g., 5G-CN) may already havestored what types of network slice/service are supported by which eLTEeNBs/cells and NR gNBs/cells. Therefore, NR gNB/cell 1606 may send NG-Csignaling to the core network including UE 1602's request networkslice/service. The core network may retrieve the information of suitableeLTE eNB s/cells and NR gNB s/cells, and provide the list of suitableeLTE eNB/cell and NR gNB/cell IDs to NR gNB/cell 1606 through NG-Csignaling. NR gNB/cell 1606 may either filter the list (e.g., remove theblocked cells) before transmitting it to UE 1602, or directly transmitthe list to UE 1602 without any modification.

After NR gNB/cell 1606 acquires the information regarding which NR gNBs/cells and eLTE eNB s/cells support UE 1602's network slice/servicerequest, NR gNB/cell 1606 may respond to UE 1602 with RRC message (e.g.,RRC Connection Reject or RRC Connection Reconfiguration), where the RRCmessage includes information such as target NR gNB/cell/beam or LTEeNB/cell or eLTE eNB/cell ID, and/or a list of suitable NR gNB/cell/beamIDs and/or LTE eNB/cell IDs and/or eLTE eNB/cell IDs, and/or specificpreamble of the target NR gNB/cell or LTE eNB/cell or eLTE eNB/cell,and/or target NR SS block/burst/burst set configuration, and/or a listof suitable NR SS block/burst/burst set configurations, as illustratedin FIG. 16. The SS block/burst/burst set may include synchronizationsignals and/or reference signals for UE 1602 to do measurements. Thus,UE 1602 may perform measurements to the target NR gNB/cell/beam or LTEeNB/cell or eLTE eNB/cell or a list of NR gNB s/cells/beams or LTEeNBs/cells or eLTE eNBs/cells. Moreover, with the information ofpreamble, the target node/cell may regard UE 1602 as a special UE, andprovide UE 1602 with privilege during the random access procedure.Providing the beam information and the SS block/burst/burst setconfigurations to UE 1602 may be beneficial, when different beams cansupport different network slices/services (different numerology/TTIlength configurations) in NR.

In other implementations, NR gNB/cell 1606 may directly select a targetNR gNB/cell or a target LTE eNB/cell or a target eLTE eNB/cell for UE1602, and send an RRC message (e.g., RRC Connection Reject or RRCConnection Reconfiguration) including the cell ID, and/or preamble,and/or beam ID (if supported), and/or SS block/burst/burst setconfiguration (if supported) of a target NR gNB/cell or a target LTEeNB/cell or a target eLTE eNB/cell to UE 1602. UE 1602 may performMCG-related/SCG-related procedures (e.g., handover to another masternode that supports the required/requested network slice/service, theinter-MN handover without the change of the secondary node, beamchange/addition/modification, or secondary nodechange/addition/modification so that the new/target secondary nodesupports the required/requested network slice/service) for slice-drivenmobility management. In the present implementation, UE 1602 may havemulti-connectivity with a number of base stations to support the networkslice/service. It is noted that the NR gNB s/cells and eLTE eNBs/cellschosen by NR gNB/cell 1606 may at least provide the network slicefunction, and optionally provide UE 1602's specific request networkslice/service.

In other implementations, the RRC message for rejection may include aprohibit timer. The prohibit timer may be activated either when NRgNB/cell 1606 sends the RRC message for rejection or when UE 1602receives the RRC message for rejection. Once the prohibit timer isactivated, UE 1602 may not be allowed to camp to NR gNB/cell 1606 untilthe prohibit timer expires. In other implementations, once the prohibittimer is activated, UE 1602 cannot request the same networkslice/service from any base station until the prohibit timer expires.The prohibit timer stops either when the prohibit timer expires or whenNR gNB/cell 1606 updates its network slice support (e.g., UE 1602 mayconstantly monitor slice support while the prohibit timer is running).

Case 2C: NR gNB/Cell Accepts UE's Request with RRC Message.

FIG. 17 is a diagram illustrating an NR gNB/cell accepting network sliceinquiry, according to an exemplary implementation of the presentdisclosure. As illustrated in FIG. 17, in action 1712, UE 1702 sends anetwork slice/service request through an RRC message, such as an RRCMessage for Request (e.g., including UE ID, Slice IDs/NSIndication/Slice Bitmap) to NR gNB/cell 1706. In action 1714, NRgNB/cell 1706 reads the RRC message including UE 1702's networkslice/service request, and decides to provide such network slice/serviceon its own. NR gNB/cell 1706 may reply to UE 1702 with an RRC message,such as an RRC Message for Connection Setup (e.g., RRC Connection Setupor RRC Reconfiguration) to build a connection or reconfigure theconnection for the required/requested network slice/service between UE1702 and NR gNB/cell 1706, as shown in FIG. 17. Upon receiving the RRCmessage, UE 1702 responds with another RRC message, such as an RRCMessage for Complete Connection (e.g., RRC Connection Complete or RRCReconfiguration Complete) to show its acknowledgement as shown in FIG.17.

FIG. 18 is a diagram illustrating an MCG bearer and an MCG split bearer(e.g., a split bearer) with an NR gNB/cell as a master node, accordingto an exemplary implementation of the present disclosure. When NRgNB/cell 1840 is a master node, the network slice/service can berealized through an MCG bearer on its own or through an MCG split bearerif a secondary node supports the RAN part of slicing, as shown in FIG.18. As shown in FIG. 18, NR gNB/cell 1840 may be a master node in anMCG, and may include SDAP layer 1842, PDCP layer 1844, RLC layer 1846,MAC layer 1848, and PHY layer 1850. eLTE eNB/cell 1820 may be asecondary node in the SCG, and may include SDAP layer 1822, PDCP layer1824, RLC layer 1826, MAC layer 1828, and PHY layer 1830. The MCG bearerand MCG split bearer in FIG. 18 may be substantially similar to the MCGbearer and MCG split bearer, respectively, as described with referenceto FIG. 10. Thus, the details of the MCG bearer and MCG split bearer areomitted for brevity.

FIG. 19 is a diagram illustrating an SCG bearer and an SCG split bearer(e.g., a split bearer) with an NR gNB/cell as a secondary node,according to an exemplary implementation of the present disclosure. WhenNR gNB/cell 1940 is a secondary node, an SCG bearer may be used toprovide the network slice/service. Also, an SCG split bearer can be usedto provide the network slice/service if a master node supports the RANpart of slicing, as shown in FIG. 19.

As shown in FIG. 19, eLTE eNB/cell 1920 may be a master node in the MCG,and may include SDAP layer 1922, PDCP layer 1924, RLC layer 1926, MAClayer 1928, and PHY layer 1930. NR gNB/cell 1940 may be a secondary nodein an SCG, and may include SDAP layer 1942, PDCP layer 1944, RLC layer1946, MAC layer 1948, and PHY layer 1950. The SCG bearer and SCG splitbearer in FIG. 19 may be substantially similar to the SCG bearer and SCGsplit bearer, respectively, as described with reference to FIG. 11.Thus, the details of the SCG bearer and SCG split bearer are omitted forbrevity.

Case 3: UE Monitors Network Slice Capability Provided by NR gNB/Cell.

An NR gNB/cell may broadcast its network slice capability either viaminimum System Information (SI) or via other SI. If the information isprovided by other SI, it can be broadcast or unicast by the NR gNB/cell.Upon receiving the SI, a UE can identify whether it is able to performthe required/requested network slice/service to the secondary node. TheNR gNB/cell may be in an MCG or an SCG. That is, the signaling fordelivering the system information can be sent via an MCG SRB, an MCGsplit SRB, an SCG SRB, or an SCG split SRB. In another implementation,the system information message generated by the NR gNB/cell as asecondary node is embedded in a master node's RRC message, and deliveredby the master node's RRC message.

Case 3A: UE Monitors NR gNB/Cell's Network Slice Capability Provided byMinimum SI of the NR gNB/Cell.

FIG. 20 is a diagram illustrating providing network slice via minimumSI, according to an exemplary implementation of the present disclosure.As illustrated in FIG. 20, in action 2062, NR gNB/cell 2004 maybroadcast minimum SI including Slice IDs and/or NS Indication and/orSlice Bitmap. If slice IDs are broadcast, NR gNB/cell 2004 directlyinforms the system (including UE 2002) what network slices/services aresupported. Thus, U E 2002 can identify by itself whether therequired/requested network slice/service is supported by NR gNB/cell2004. When NR gNB/cell 2004 broadcasts an NS Indication, NR gNB/cell2004 reveals its network slice capability instead of the exact supportednetwork slices/services. As such, UE 2002 can further inquire/request NRgNB/cell 2004 about what exact network slice/service is supported viadedicated signaling if UE 2002 has the network slice/servicerequirement. When NR gNB/cell 2004 broadcasts a slice bitmap, NRgNB/cell 2004 explicitly reveals the specific supported network slices.In action 2064, UE 2002 may identify whether the required/requestednetwork slice service is supported by NR gNB/cell 2004 based on theminimum SI broadcast by NR gNB/cell 2004.

Case 3B: UE Monitors NR gNB/Cell's Network Slice Capability Provided byOther SI of the NR gNB/Cell.

FIG. 21 is a diagram illustrating providing network slice via other SI,according to an exemplary implementation of the present disclosure. InFIG. 21, NR gNB/cell 2104 may broadcast or unicast its network slicecapability and/or the supported network slice/service via other SI(e.g., on demand SI). In action 2172, UE 2102 may first request theother SI from NR gNB/cell 2104 (e.g., via an SI Request messageincluding NS Indication, which means UE 2102 needs more SI informationregarding to the network slice/service from the NR gNB/cell.) In action2174, NR gNB/cell 2104 may send a reply message including NR gNB/cell2104's supported network slices/services (e.g., via Slice ID and/orSlice Bitmap) and/or its network slice capability (e.g., via NSIndication), in the other SI. In action 2176, UE 2102 may identifyand/or determine whether the required/requested network slice/service issupported by NR gNB/cell 2104 based on the other SI from NR gNB/cell2104.

Case 3C: UE Monitors Neighboring Cells' Network Slice CapabilitiesProvided by Other SI of the NR gNB/Cell.

FIG. 22 is a diagram illustrating a neighboring cell's network slice viaother SI, according to an exemplary implementation of the presentdisclosure. As illustrated in FIG. 22, in action 2272, UE 2202 may sendan RRC message (e.g., SI Request, such as an RRCSystemInfoRequestmessage) to NR gNB/cell 2204, where the RRC message may include NSIndication and/or Slice Bitmap and/or Slice IDs for asking network slicesupport, or NS Indication and/or Slice Bitmap and/or Slice IDs ofneighboring NR gNB s/cells/beams and/or eLTE eNB s/cells for the networkslice support from neighboring nodes/cells/beams. NR gNB/cell 2204 mayreveal the neighboring gNB s/cells/beams' and/or eLTE eNB s/cells'supported network slices/services (e.g., with the combination of SliceIDs and/or Slice Bitmap and neighboring NR gNB/cell/beam and/or eLTEeNB/cell IDs) and/or the network slice capabilities (e.g., thecombination of NS Indication and neighboring NR gNB/cell/beam and/oreLTE eNB/cell IDs, or only the neighboring NR gNB/cell/beam and/or eLTEeNB/cell IDs which support) in the other SI. In action 2276, UE 2202 maydetermine and/or identify whether the required/requested networkslice/service is supported by any neighboring NR gNBs/cells/beams and/oreLTE eNBs/cells, based on which UE 2202 may further perform the mobilitymanagement procedures such as cell (re)selection, measurement,SCG-related procedures (e.g., change/addition/modification of secondarynode), and MCG-related procedures (e.g., handover to another master nodewhich supports the required/requested network slice/service, or theinter-MN handover without the change of the secondary node).

In some exemplary implementations, the UE may first check whether theserving NR gNB/cell or eLTE eNB/cell can support the required/requestednetwork slice or network slice capability. If the serving NR gNB/cell oreLTE eNB/cell cannot support the required/requested network slice ornetwork slice capability, the UE may further ask for information ofneighboring NR gNBs/cells/beams and eLTE eNB s/cells for network slicesupport (e.g., as shown in FIG. 22). In some exemplary implementations,the UE may request for information of neighboring NR gNBs/cells/beamsand eLTE eNB s/cells for network slice support via preamble, and/or MSG3, and/or MSG 5. The NR gNB/cell may response with MSG 2 and/or MSG 4and/or specific configured resources. It is noted that control signalingexchanged among the NR gNB/cell and the neighboring NR gNBs/cells andeLTE eNBs/cells may occur through/in Xx/Xn interface. The controlsignaling exchange may involve information exchange such as NSIndication of neighboring NR gNBs/cells/beams and/or eLTE eNBs/cells,and/or Slice IDs or Slice Bitmaps of neighboring NR gNBs/cells/beamsand/or eLTE eNBs/cells, and/or the list of neighboring NR gNB/cell/beamand/or eLTE eNB/cell IDs.

Case 4: If UE's Required Network Slice/Service is not Supported by NRgNB/Cell and eLTE eNB/Cell, Mobility Management Procedures are Triggeredto Fulfill UE's Required Network Slice/Service.

When a UE may recognize that the required/requested networkslice/service is not supported by its master node and/or the secondarynode, the UE, the master node, the secondary node, the core network, orany combination thereof may trigger mobility management procedures(e.g., intra-MN handover, inter-MN handover, intra-SN handover, inter-SNhandover, MCG-related procedures, SCG-related procedures, inter-MNhandover without the change of the secondary node, inter-SN handoverwithout the change of the master node, secondary nodechange/addition/modification, or beam change/addition/modification) tosatisfy the UE's required/requested network slice/service. It is notedthat the master node and the secondary node can be the NR gNB/celland/or the eLTE eNB/cell. It is noted that the selected master node orsecondary node may or may not support the UE's required networkslice/service. For example, the selected master node or secondary nodemay support the network slice/service, that is not required by the UE.In some implementations, the UE may request the required the networkslice/service from the target master node or target secondary node. Theresult of the mobility management procedures may lead to dualconnectivity or multi-connectivity.

The mobility management procedures may also involve information exchangein Xx/Xn interface and NG-C interface, such as UE ID, Slice IDs/Slicebitmap/NS Indication, target NR gNB/cell/beam or LTE eNB/cell or eLTEeNB/cell ID, and/or a list of suitable NR gNB/cell/beam IDs and/or LTEeNB/cell IDs and/or eLTE eNB/cell IDs, and/or specific preamble of thetarget NR gNB/cell or LTE eNB/cell or eLTE eNB/cell, and/or target NR SSblock/burst/burst set configuration, and/or a list of suitable NR SSblock/burst/burst set configurations.

Case 4A: Master Node Change—Handover to Another Master Node thatSupports UE's Required Network Slice/Service.

A UE may perform handover to another master node, while the secondarynode may remain unchanged. The UE may measure the signal from a coupleof NR gNBs/cells and/or eLTE eNBs/cells, which support the UE'srequired/requested network slice/service or support the network slice.The list of the NR gNBs/cells and/or eLTE eNBs/cells may be provided bythe master node and/or the secondary node, for example, in the form of alist of (neighboring) NR gNB/cell and/or eLTE eNB/cell IDs/objects,which support the required/requested network slice/service and/or thenetwork slice capability. The list of NR gNBs/cells and/or eLTEeNBs/cells, to which the UE measures signal, may be preconfigured. Forexample, the UE may be preconfigured to know on which frequency therequired/requested network slice/service is provided.

Based on the measurement report, the UE may select the target masternode on its own and report the decision to the source master node. Inanother implementation, the UE may report the measurement result to thesource master node, and allow the source master node to select a targetmaster node. It is noted that signaling in Xx/Xn interface among thesource master node, the target master node, the source secondary node,and the target secondary node (if needed) may be utilized.

Case 4B: Secondary Node Change—(Re)Select a Secondary Node/Intra-SNHandover to Another Secondary Node/Modify Existing Secondary Node.

A UE may select or reselect a secondary node, intra-SN handover toanother secondary node, or modify the existing secondary node, tosupport the required/requested network slice/service, while the masternode may remain unchanged. The secondary node may be selected by the UEor by the master node based on measurement results. The reselectedsecondary node(s) may also be assigned by the core network (e.g.,5G-CN). For example, the UE may measure a number of NR gNB s/cells thatsupport the required/requested network slice/service. The information ofthe number of NR gNB s/cells may be provided by the master node or thesource secondary node to the UE, for example, in the form of a list of(neighboring) NR gNB/cell IDs/objects. In other cases, the UE may bepreconfigured to know on which frequency the required/requested networkslice/service is supported. It is noted that the selected secondary nodemay be NR gNBs/cells and/or eLTE eNBs/cells.

Based on the measurement report, the UE may select the target secondarynode and report the decision to the source master node. In anotherimplementation, the UE may report the measurement result to the sourcemaster node, and allow the source master node to select a target masternode. It is noted that signaling in Xx/Xn interface among the sourcemaster node, the source secondary node, and the target secondary nodemay be utilized. In some implementations, the NG-C signaling exchangebetween the master node and the 5G-CN may be also needed. Thereafter,the corresponding RRC message exchange between the UE and the masternode, or between the UE and the target secondary node, may be utilized.

Case 4C: Secondary Node Addition—Add a New Secondary Node that SupportsUE's Required Network Slice/Service.

A UE may add a new secondary node that supports the required/requestednetwork slice/service. The added secondary node may be an NR gNB/cell oran eLTE eNB/cell. The added secondary node may be selected by the UE, bythe master node, by the existing secondary nodes, or by the core network(e.g., 5G-CN). The selection may be based on the measurement resultand/or the matched supported network slice/service. For example, the UEmay measure a number of NR gNBs/cells and/or eLTE eNB s/cells thatsupport the required/requested network slice/service. The information ofthe number of NR gNBs/cells and/or eLTE eNBs/cells may be provided bythe master node or the existing secondary nodes or the core network tothe UE, for example, in the form of a list of (neighboring) NR gNB/cellIDs/objects and/or (neighboring) eLTE eNB/cell IDs/objects. In othercases, the UE may be preconfigured to know on which frequency therequired/requested network slice/service is supported.

Based on the measurement report, the UE may select the new secondarynode on its own and report the decision to the source master node and/orthe existing secondary nodes. In another implementation, the UE mayreport the measurement result to the source master node and/or theexisting secondary nodes, and allow the source master node and/or theexisting secondary nodes to select a target master node. It is notedthat the signaling in Xx/Xn interface among the source master node, theexisting secondary nodes, and the added secondary node may be utilized.The NG-C signaling between the master node and the 5GC may also beneeded. Thereafter, the corresponding RRC message exchange between theUE and the master node, and/or between the UE and the added secondarynode and/or between the UE and the existing secondary nodes, may beutilized.

In some implementations, when the master node cannot support the networkslice/service but the secondary node can, or when the secondary nodecannot support the network slice/service but the master node can, themobility management procedures in Cases 4A, 4B, and 4C can also beperformed.

Case 5: UE Monitors eLTE eNB/Cell's Network Slice Capability Broadcast.

FIG. 23 is a diagram illustrating an eLTE eNB/cell broadcasting itsnetwork slice capability, according to an exemplary implementation ofthe present disclosure. As illustrated in FIG. 23, in action 2382, eLTEeNB/cell 2304, as a master node or a secondary node, may broadcast SliceIDs and/or NS Indication and/or Slice Bitmap. When slice IDs arebroadcast, eLTE eNB/cell 2304 may directly inform UE 2302 what networkslices/services are supported. In action 2384, UE 2302 may determine oridentify whether the required/requested network slice/service issupported by the eLTE eNB/cell. When an NS Indication is broadcast, eLTEeNB/cell 2304 may reveal its network slice capability instead of theexact network slice/service supported. UE 2302 may further inquire orrequest the eLTE eNB/cell about exactly what network slice/service issupported by eLTE eNB/cell 2304 via dedicated signaling if UE 2302 hasthe network slice/service requirement. When a slice bitmap is broadcast,eLTE eNB/cell 2304 may explicitly reveal the specific supported networkslices. It is noted that the broadcast message (e.g., System InformationBlock (SIB)) may be delivered via an MCG SRB, an MCG split SRB, an SCGSRB, or an SCG split SRB.

Case 6: Idle/Inactive UE Camps to a Suitable RAT that Supports UE'sRequired Network Slice During Cell (Re)Selection.

An idle/inactive UE may camp or select/reselect a cell of a suitable RATthat supports the required/requested network slice/service.

Case 6A: UE's NAS is Preconfigured to have Information of Network SliceSupport.

FIG. 24 is a diagram illustrating cell (re)selection based on networkslice, according to an exemplary implementation of the presentdisclosure. In action 2492, a UE's Non Access Stratum (NAS) may firstidentify a selected PLMN (Public Land Mobile Network) and the equivalentPLMNs. The UE's NAS is preconfigured to have the information of whichRAT/frequency band supports the network slice or even specific networkslice/service. The UE's NAS may forward the information to the AccessStratum (AS). As such, the UE′ AS with network slice requirement maymonitor and measure signal from/on the RATs/frequency bands. In FIG. 24,in action 2494, the UE's NAS or AS may identify the required/requestednetwork slice/service and/or the network slice support (e.g., via sliceIDs and/or NS Indication and/or Slice Bitmap). In action 2496, the UEmay search the RATs/frequency bands on which the required/requestednetwork slice/service and/or network slice capability are supported. Itis noted that the RATs/frequency bands that the UE monitors on may beassociated with the selected PLMN or the equivalent PLMNs. In otherimplementations, the AS may try to receive/measure all RATs/frequencybands, and acquire relative slicing information. After collecting theslicing information, the AS forwards the information to the NAS, whichmay decide which RATs/frequency bands are appropriate. Thereafter, theNAS may notify its decision to the AS, and perform RRC connectionestablishment with the corresponding RAT/frequency. It is noted that theAS may filter out the RATs/frequency bands with signal quality below apredetermined threshold.

Case 6B: UE Performs Cell (Re)Selection and Camps to a RAT that SupportsRequired Network Slice Based on a List of Barred Cells.

A UE is (pre)configured with a list of barred cells, which cannotsupport network slice and/or specific network slice/service. In someimplementations, the UE is (pre)configured with a list of barred cells,which cannot generally support the network slices. In someimplementations, the UE is (pre)configured with a list of barred cellsfor each specific network slice. For example, for each slice ID, thereis a list of barred cells. The UE may be (pre)configured with therelationship between a portion (or all) of the slices and theircorresponding lists of barred cells. The list of barred cells can be alist of barred cells' IDs. The list may be preconfigured and/or modifiedwhen the UE receives the broadcast information from NR gNBs/cells andeLTE eNBs/cells about their network slice supports. With the list, afterthe UE may determine the PLMNs and performs measurement, the suitablecells to camp on can be selected based on the list of barred cells.

Case 7: eLTE eNB/Cell Performs Inter-System Intra-RAT Handover toSupport UE's Required Network Slice.

When an eLTE eNB/cell needs to support a network slice, the eLTEeNB/cell may perform inter-system intra-RAT handover, as shown in FIG.25, for example, from Case 500D in FIG. 5D to Case 500B in FIG. 5B. FIG.25 is a diagram illustrating inter-system intra-RAT handover, accordingto an exemplary implementation of the present disclosure. In theinter-system intra-RAT handover, the S1-C and NG-C interfaces mayinvolve slice-related information exchange, which includes, for example,capability of network slice support and/or the types of network slices(e.g., RAN slice ID and/or CN slice ID). In the inter-system intra-RAThandover, NAS signaling carried in the RRC message including the sliceinformation may be utilized in a Uu interface, when the eLTE eNB/cellchanges the serving core network of the UE. In some implementations, theUE may connect with EPC 2506 and 5G-CN 2508 simultaneously. In suchcase, the UE may connect with a source CN (e.g., EPC 2506 or 5G-CN 2508)through eLTE eNB 2504. eLTE eNB 2504 may assist the UE to connect with atarget CN while the original connection with the source CN is still keptby eLTE eNB 2504. This situation may happen when the UE'srequired/requested network slice is served by a specific CN. Forexample, the UE is connected with EPC 2506, then wants to activate aservice, such as URLLC, which can be provided only by 5G-CN 2508'snetwork slice. The UE needs to inform eLTE eNB 2504 that it is capableto connect with EPC 2506 and 5G-CN 2508 simultaneously. eLTE eNB 2504may also need to inform the UE that eLTE eNB 2504 is capable to connectwith EPC 2506 and 5G-CN 2508 simultaneously. Once the UE is connectedwith EPC 2506 and 5G-CN 2508 simultaneously, the UE may keep twodifferent upper layers (e.g., one NAS layer for EPC 2506, and anotherNAS layer for 5G-CN 2508). In another example, the UE may have one upperlayer but two separate configurations (e.g., two instances, one for EPC2506, and another one for 5G-CN 2508). That is, a shared upper layer(e.g., NAS) and two independent configurations (e.g., instances) for EPC2506 and 5G-CN 2508.

Case 8: UE Performs Mobility Management to Change Anchor Node to TargetNR gNB/Cell or eLTE eNB/Cell.

A UE may perform mobility management to change its anchor node to atarget NR gNB/cell or eLTE eNB/cell that supports the UE'srequired/updated network slice. In some implementations, the networkslice in the source NR gNB/cell or eLTE eNB/cell is maintained. The UEmay maintain the original network slice in the source NR gNB/cell oreLTE eNB/cell.

In some implementations, when the UE performs mobility management tochange the anchor to the target NR gNB/cell or eLTE eNB/cell, whichsupports the UE's required/requested network slice, the configurationfor new radio bearers (e.g., SDAP/PDCP/RLC/MAC/PHY configuration) torealize the network slice in the target NR gNB/cell or eLTE eNB/cell isprovided to the UE by the source/target NR gNB/cell or eLTE eNB/cell.

In some implementations, the configuration for new radio bearers (e.g.,SDAP/PDCP/RLC/MAC/PHY configuration) to realize the UE's request networkslice in the target NR gNB/cell or eLTE eNB/cell may be provided to theUE by the source NR gNB/cell or eLTE eNB/cell. The UE may keep thecontrol plane anchor to the source/target NR gNB/cell or eLTE eNB/cell.

Case 9: RAN Notification Area Update Considering UE's Network SliceRequirements.

FIG. 26 is a diagram illustrating RAN notification area update withnetwork slice support, according to an exemplary implementation of thepresent disclosure. For example, when UE 2602 is in RRC_(—) INACTIVEstate and has some network slices, a RAN notification area updateprocedure may consider UE 2602's network slice requirements. WhenRRC_INACTIVE UE 2602 moves out of the RAN notification area, and findsthe received RAN area ID and/or NR gNB/cell ID (e.g., from target NRgNB/cell/RAN 2604) is not in its RAN notification area (e.g., source NRgNB/cell/RAN 2606), in action 2612, UE 2602 may send an RRC message(e.g., RRC Resume) including its UE ID and/or source NR gNB/cell 2606'sID and/or source RAN area ID and/or NS Indication/Slice ID/Slice Bitmapto target NR gNB/cell/RAN 2604. The cause of the RRC message sent by theUE may be “RAN notification area update request”. Source NR gNB/cell2606's ID and source RAN area ID are in the UE's original RANnotification area. In action 2614, target NR gNB/cell/RAN 2604 mayperform UE context retrieval and UE authentication and RAN notificationarea inquiry with 5G-CN 2608 and/or source NR gNB/cell/RAN 2604. Xx/Xnsignaling and NG-C signaling including UE 2602's ID and UE 2602's sliceID, NS Indication, and/or Slice Bitmap may be utilized for target NRgNB/cell/RAN 2604 to confirm UE 2602's status, to retrieve UE 2602'scontext from source NR gNB/cell/RAN 2606, and to coordinate with 5G-CN2608 and/or source NR gNB/cell/RAN 2606 for the list of possible NRgNBs/cells/RANs with UE 2602's corresponding network slice support andrequirement from 5G-CN 2608 and/or source NR gNB/cell/RAN 2606.Therefore, the RRC message (e.g., RAN notification area update message)sent from target NR gNB/cell/RAN 2604 to UE 2602 may include the NRgNB/cell IDs and/or RAN area IDs which support UE 2602's network slice.The cause of this RRC message may be RAN notification area update. Forexample, the RAN notification area update message sent to UE 2602includes the IDs of NR gNB/cell and/or RAN area IDs, which support UE2602's network slice requirements and/or the specific network slice.That is, when 5G-CN 2608 and/or NR gNB/cell RAN 2604/2606 determine theRAN notification area for UE 2602, only the NR gNBs/cells and/or RANswhich can support UE 2602's network slice requirement and/or thespecific slice are considered.

In some implementations, for example, the NR gNBs/cells/RANs in theupdated RAN notification area may not support the UE's network slicerequirement. Thus, the UE may not camp to the NR gNBs/cells/RANs in theupdated RAN notification area which does not support its network slice.That is, whatever the updated RAN notification area is, the inactive UEmay only camp to an NR gNB/cell provided in the updated RAN notificationarea message, where the NR gNB/cell supports the UE's network slicerequirement and/or the specific network slice. In such case, the RANnotification area determined by the core network and/or NR gNB/cell forthe inactive UE is not based on the UE's network slice requirementand/or specific slice. However, the UE may only camp to the NR gNB/celland/or RAN in the indicated RAN notification area, which can support theUE's network slice requirement. The UE may determine whether an NRgNB/cell supports the UE's network slice requirement and/or the specificnetwork slice based on the NR gNB/cell's broadcast message, which mayinclude NS Indication and/or Slice IDs and/or Slice Bitmap.

In the aforementioned cases 1-9, whenever the UE responds to the NRgNB/cell and/or the eLTE eNB/cell with Slice IDs/NS Indication/SliceBitmap/UE IDs/NS Indication of neighboring NR gNBs/cells/beams/NSIndication of neighboring eLTE eNBs/cells, the UE may utilize MSG 1, MSG3 or MSG 5, which may also be utilized for communications between theLTE eNB/cells and the UE.

FIG. 27 illustrates a block diagram of a node for wirelesscommunication, in accordance with various aspects of the presentapplication. As shown in FIG. 27, node 2700 may include a transceiver2720, a processor 2726, a memory 2728, one or more presentationcomponents 2734, and at least one antenna 2736. The node 2700 may alsoinclude an RF spectrum band module, a base station communicationsmodule, a network communications module, and a system communicationsmanagement module, input/output (I/O) ports, I/O components, and powersupply (not explicitly shown in FIG. 27). Each of these components maybe in communication with each other, directly or indirectly, over one ormore buses 2740.

The transceiver 2720 having a transmitter 2722 and a receiver 2724 maybe configured to transmit and/or receive time and/or frequency resourcepartitioning information. In some implementations, the transceiver 2720may be configured to transmit in different types of subframes and slotsincluding, but not limited to, usable, non-usable and flexibly usablesubframes and slot formats. The transceiver 2720 may be configured toreceive data and control channels.

The node 2700 may include a variety of computer-readable media.Computer-readable media can be any available media that can be accessedby the node 2700 and include both volatile and non-volatile media,removable and non-removable media. By way of example, and notlimitation, computer-readable media may comprise computer storage mediaand communication media. Computer storage media includes both volatileand non-volatile, removable and non-removable media implemented in anymethod or technology for storage of information such ascomputer-readable instructions, data structures, program modules orother data.

Computer storage media includes RAM, ROM, EEPROM, flash memory or othermemory technology, CD-ROM, digital versatile disks (DVD) or otheroptical disk storage, magnetic cassettes, magnetic tape, magnetic diskstorage or other magnetic storage devices. Computer storage media doesnot comprise a propagated data signal. Communication media typicallyembodies computer-readable instructions, data structures, programmodules or other data in a modulated data signal such as a carrier waveor other transport mechanism and includes any information deliverymedia. The term “modulated data signal” means a signal that has one ormore of its characteristics set or changed in such a manner as to encodeinformation in the signal. By way of example, and not limitation,communication media includes wired media such as a wired network ordirect-wired connection, and wireless media such as acoustic, RF,infrared and other wireless media. Combinations of any of the aboveshould also be included within the scope of computer-readable media.

The memory 2728 may include computer-storage media in the form ofvolatile and/or non-volatile memory. The memory 2728 may be removable,non-removable, or a combination thereof. Exemplary memory includessolid-state memory, hard drives, optical-disc drives, and etc. Asillustrated in FIG. 27, The memory 2728 may store computer-readable,computer-executable instructions 2732 (e.g., software codes) that areconfigured to, when executed, cause the processor 2726 to performvarious functions described herein, for example, with reference to FIGS.1 through 26. Alternatively, the instructions 2732 may not be directlyexecutable by the processor 2726 but be configured to cause the node2700 (e.g., when compiled and executed) to perform various functionsdescribed herein.

The processor 2726 may include an intelligent hardware device, e.g., acentral processing unit (CPU), a microcontroller, an ASIC, and etc. Theprocessor 2726 may include memory. The processor 2726 may process thedata 2730 and the instructions 2732 received from the memory 2728, andinformation through the transceiver 2720, the base band communicationsmodule, and/or the network communications module. The processor 2726 mayalso process information to be sent to the transceiver 2720 fortransmission through the antenna 2736, to the network communicationsmodule for transmission to a core network.

One or more presentation components 2734 presents data indications to aperson or other device. Exemplary presentation components 2734 include adisplay device, speaker, printing component, vibrating component, andetc.

From the above description it is manifest that various techniques can beused for implementing the concepts described in the present applicationwithout departing from the scope of those concepts. Moreover, while theconcepts have been described with specific reference to certainimplementations, a person of ordinary skill in the art would recognizethat changes can be made in form and detail without departing from thescope of those concepts. As such, the described implementations are tobe considered in all respects as illustrative and not restrictive. Itshould also be understood that the present application is not limited tothe particular implementations described above, but many rearrangements,modifications, and substitutions are possible without departing from thescope of the present disclosure.

-   ¹ 3GPP TR 38.801, “Study on New Radio Access Technology; Radio    Access Architecture and Interfaces”.-   ² RAN2 #94 Chairman notes.-   ³ TR 38.804, “Study on New Radio Access Technology; Radio Interface    Protocol Aspects”.-   ⁴ TR 38.801, “Study on New Radio Access Technology; Radio Access    Architecture and Interfaces”.-   ⁵ TR 23.799, “Study on Architecture for Next Generation System”.

What is claimed is:
 1. A user equipment (UE) comprising: anon-transitory machine-readable medium storing computer-executableinstructions; at least one processor coupled to the non-transitorycomputer-readable medium, and configured to execute thecomputer-executable instructions to: determine whether a requirednetwork slice/service of the UE is supported by a network node; performat least one of a plurality of mobility management procedures, when therequired network slice/service of the UE is not supported by the networknode; wherein the plurality of mobility management procedures includes:selecting another master node (MN), or intra-MN handover or inter-MNhandover to another MN; selecting or reselecting a secondary node (SN),intra-SN handover to another SN, modifying an existing SN, or adding anew SN; changing the UE's anchor node to a target new radio (NR) nextgeneration node B (gNB) or a target evolved long term evolution (eLTE)evolved node B (eNB).
 2. The UE of claim 1, wherein the at least oneprocessor is further configured to execute the computer-executableinstructions to: send a System Information (SI) request to the networknode; and receive network slice capability in other SI broadcast orunicast by the network node; wherein the network slice capabilityindicates one or more network slices or services supported by thenetwork node.
 3. The UE of claim 2, wherein at least one of the minimumSI or the other SI includes at least one of a Slice ID, a Network SliceIndication, or a Slice Bitmap.
 4. The UE of claim 1, wherein the atleast one processor is further configured to execute thecomputer-executable instructions to: send a radio resource control (RRC)message to the network node for network slice support information of atleast one neighboring network node; receive the network slice supportinformation of the at least one neighboring network node from the otherSI broadcast or unicast by the network node; determine, based on thenetwork slice support information, whether the required networkslice/service of the UE is supported by the at least one neighboringnetwork node.
 5. The UE of claim 1, wherein the network node isconnected to a 5G core network.
 6. The UE of claim 1, wherein, whenselecting the another MN or selecting or reselecting the SN, the UEmeasures signals from a list of neighboring network nodes broadcast orunicast by the network node, and selects the another MN or the SN basedon the measurement.
 7. The UE of claim 1, wherein the UE receives aradio access network (RAN) notification area update through a 5G corenetwork, the RAN notification area update includes at least one of alist of NR gNB/cell IDs or a list of RAN area IDs, wherein the list ofNR gNB/cell IDs corresponds to a list of NR gNBs/cells that support therequired network slice/service of the UE, and the list of RAN area IDscorresponds to a list of the RAN areas that support the required networkslice/service of the UE.
 8. The UE of claim 1, wherein: a Non-AccessStratum (NAS) of the UE provides the information of the required networkslice/service to an Access Stratum (AS) of the UE; the AS monitorssignals from the network node; the AS identifies the required networkslice/service through at least one of a Slice ID, a Network SliceIndication, and a Slice Bitmap from the signals.
 9. The UE of claim 1,wherein the UE is configured to have a list of barred cells that do notsupport the required network slice capability.
 10. A network nodecomprising: a non-transitory machine-readable medium storingcomputer-executable instructions; at least one processor coupled to thenon-transitory computer-readable medium, and configured to execute thecomputer-executable instructions to: provide network slice capability ofthe network node to a user equipment (UE); perform at least one of aplurality of mobility management procedures, when the network slicecapability of the network node does not support a required networkslice/service of the UE; wherein the plurality of mobility managementprocedures includes: selecting another master node (MN), or intra-MNhandover or inter-MN handover to another MN; selecting or reselecting asecondary node (SN), intra-SN handover to another SN, or modifying anexisting SN; adding a new SN; changing the UE's anchor node to a targetnew radio (NR) next generation node B (gNB) or a target evolved longterm evolution (eLTE) evolved node B (eNB).
 11. The network node ofclaim 10, wherein the network node is in a master cell group or asecondary cell group.
 12. The network node of claim 10, wherein thenetwork node is connected to a 5G core network.
 13. The network node ofclaim 10, wherein the network slice capability is broadcast or unicastby the network node via minimum SI or other SI.
 14. The network node ofclaim 13, wherein at least one of the minimum SI or the other SIincludes at least one of a Slice ID, a Network Slice Indication, or aSlice Bitmap.
 15. The network node of claim 10, wherein the networkslice capability is broadcast or unicast through a Signaling RadioBearer (SRB).
 16. The network node of claim 10, wherein the at least oneprocessor is further configured to execute the computer-executableinstructions to: receive an SI request from the UE; and broadcast orunicast the network slice capability in other SI to the UE.
 17. Thenetwork node of claim 10, wherein the at least one processor is furtherconfigured to execute the computer-executable instructions to: broadcastor unicast network slice support information of at least one neighboringnetwork node to the UE.
 18. The network node of claim 17, wherein the atleast one neighboring network node is connected to a 5G core network.19. The network node of claim 10, wherein the network node provides theUE a radio access network (RAN) notification area update through the 5Gcore network, the RAN notification area update includes at least one ofa list of NR gNB/cell IDs or a list of RAN area IDs, wherein the list ofNR gNB/cell IDs corresponds to a list of NR gNBs/cells that support therequired network slice/service of the UE, and the list of RAN area IDscorresponds to a list of the RAN areas that support the required networkslice/service of the UE.
 20. The network node of claim 10, wherein thenetwork node provides a list of barred cells that do not support therequired network slice capability to the UE.